I was never a fan of the 28 1.8, the copies I'd seen were fairly poor performers compared to other options.
Buying a new lens in that price/focal length range? I'd be looking at the newer Canon 28 f/2.8 IS or 35 f/2 IS primes, very good performance.
If you wanted both fast aperture and wide, I'd prefer the Canon 24L, but you do have a cost/weight penalty there.
At the price point, I'd probably choose the 35 f/2 IS overall. $550 with rebate right now.